How to install Filmic Blender under Ubuntu?
SOLVED!

Under Linux Ubuntu, the colormanagement folder is located here:

/usr/share/blender/2.78/datafiles.

To rename it, since it's a system folder, you must be logged in as administrator. It's easy. I opened Thunar file manager and navigated to the folder location. Once there, I right-clicked and chose "open terminal here". In the terminal, the command is:

sudo mv colormanagement colormanagement_oldbackup

Insert your root password and it's done.
To place the new folder in here, first place the "filmic-blender" folder on your home folder (in my case it's /home/gigabyte). Rename it as colormanagement. Then, open the terminal and type:

sudo cp -R /home/yourusername/colormanagement /usr/share/blender/2.78/datafiles

Insert again your password and it's done.
Remember that you doesn't need really type the whole lines. Use "Ctrl C" to copy from the file manager (right click on the folder/file and, and you'll see the label "location"). In the terminal use "Ctrl Shift V".

The Reluctant Computer

On the computer with Ubuntu 14, I had to allow Blender to access the new colormanagement folder. To do this, you must open the terminal on the folder "datafiles". Then, type:

sudo chown -R yourusername colormanagement

The system will ask for your password and it's done.

Ok, it's a little less easy than Windows, but what can I do? I love Ubuntu...